On Monday mobile phone users, including those with Apple's iPhone, got a new way to sync and access information from the cloud. Called Google Sync, the new service lets you sync up both calendars and contacts from a specified Google account and will send changes over the air — both ways.

The service uses Microsoft Exchange's ActiveSync protocol to get the job done, and because of this can actively push changes as soon as they're made. Previously the only way to get this kind of near-instantaneous change was to sync up an existing Exchange account with Outlook using Google's other synchronisation utility, Google Calendar Sync. However, that system did not sync contacts and required users to actively run a software client on a machine that had Outlook running.

Setting up your phone to sync up with Google's servers does not require any special software, however it's worth noting that if you have an iPhone or Windows mobile handset the process will wipe out any existing contacts and calendars from your device. This data loss does not occur on Nokia, BlackBerry, Sony Ericsson, or Motorola devices. Also, users who haven't already begun using Google's contact manager are encouraged to do so, as after syncing it becomes the one place where all of your contacts are stored.

Another small caveat is that the service only currently supports up to five user calendars. Users of Google Calendar who may be used to more than that number may have problems with this solution.

One thing that's missing from the equation is Google's Gmail service, which does not offer a push service. Future versions of Google Sync may add that to the equation. Competitor Yahoo has offered a free (although sometimes flaky) push service for its web mail since the iPhone's introduction in early 2007.